Wireless charging technology (by means of electromagnetic induction) is becoming mature, and will be the mainstream means of charging intelligent terminals in the future. A back cover mobile power supply (in the case of a mobile phone, the back cover mobile power supply looks similar to the phone's back cover, which usually has an output current interface disposed in the bottom) has a built-in back battery and a control circuit. The back cover mobile power supply is covered on a back surface of the intelligent terminal, and an output current interface directly inserted into a USB interface at a bottom of the intelligent terminal. A power switch on the back cover mobile power supply can be pressed to control charging the intelligent terminal without a data cable and affecting the use of the intelligent terminal.
However, the back cover mobile power supply also needs to be powered so as to charge, and the back battery can charge the intelligent terminal after it is fully charged. The user can merely charge the back cover mobile power supply or the intelligent terminal alone, however the back cover mobile power supply and the intelligent terminal cannot be charged at the same time, which has low charging efficiency.
Therefore, there is room for improvement and development.